Life in the Cell Begins at the Edge of Death, Part 7

Part 7: A Single Cell’s Mitochondria is the Aerobic Machine of Your Body

 

CO2 exiting a single cell is conceptually identical to exhaling CO2 out of your mouth. This CO2 is made from the O2 entering the cell, which combines with the fuel/carbon in acetic acid. All the CO2 exiting your mouth results simply from the total sum of all your cells’ combustion of acetic acid.

Just as you breathe, so does a single cell.

Cellular respiration is simply a ‘cell breathing’ while acetic acid burns. This is a crude drawing made by a group of students’ first attempt to draw aerobic metabolism within just one cell.

You can see they correctly illustrated combustion where O2 flows into a cell and CO2 streams out. Notice they mistakenly wrote “Air + O2 –> CO2 + H2O. Air is not fuel, so of course they should have written ‘fuel’ or ‘acetic acid’. They also forgot to write ‘heat’ is produced, but not bad for their first college try drawing ‘combustion of food’ at the cell level.

Respiration in a single cell is analogous to a human ‘sealed-in-a-box’ (pictured below).

 

The Trapped Female Artist Sealed in a Box ‘Experiment’

 

Here’s another combustion/metabolic experiment – although accidental – showing how the entire body becomes a ‘single cell’  when sealed into a space where O2 streams in and CO2 streams out.

Look closely (click image to enlarge it); you can see a small hole in the lower cardboard square. The only way the woman could have survived for a long period of time is if she made two good vents. One for oxygen to come into her ‘cell space’ and one to vent out the CO2.

Point is, a sealed box with a breathing animal stuffed inside becomes a single cell space. The ‘cell’  must be built correctly so O2 can stream in and CO2 can stream out. In this case, it was only a short mater of time before she ‘consumed’ the limited amount of oxygen in the box and the space filled up with CO2. At any rate, she and her friends failed to vent the box properly; she almost suffocated to death before firefighters busted her out.

 

Thought Experiment #1: How does a Chick ‘Trapped’ in an Egg Breathe?

 

Answer: The egg shell is permeable to air.

This allows oxygen to pass inside and CO2 to pass out of the shell.

So a developing chick breathes ‘just fine’ before it hatches.

 

 

 

 

Thought Experiment #2: How does a Human Fetus ‘Breathe’?

 

Answer: The same way you and I do. At the cell level. Technically, respiration occurs within a cell. Respiration is combustion and combustion is aerobic metabolism.

Thus, a developing baby ‘breathes’ as oxygen combines with fuel its cells.

The mother’s blood stream carries the oxygen she breathed into her lungs, through her blood stream, and then to the baby.

So a baby ‘respires’ just like all humans do after birth. CO2 streams out of the baby’s cells, gets channeled into the mother’s blood stream, and then is exhaled by the mother.

 

 

 

 

 

Main Points:

• The cell is the machine in your body where fuel combines with oxygen.

• Our cells are not capable of burning the carbon in any food – unless broken down into acetic acid. This does not mean you can drink just vinegar to survive.

•  ‘Every breath you make” expels CO2. Your mouth is the vent for the CO2 produced by your cells deep within your body. Not as romantic as ‘every breath you take’… I know.

• Antoine Lavoisier collected CO2 gas in the 1770’s in a respiration experiment that marks the beginning of The Modern Era of Physiology and Medicine. We’re now in what I call the Postmodern Era, beginning around 1905.

 

Three Special Remarks

 

#1 – Alternative Fuels do Exist

In case you’ve been wondering… the body does indeed make and use alternative carbon fuels besides acetic acid. Examples include ketones, lactate, and others, which we will examine later. But in ‘normal physiology’ acetic acid is the primary fuel.

 

#2 – Restoring the Junk Attached to the Carbon

Look again at the structure of acetic acid; you see Hydrogen, ‘H’ is attached to the carbon atoms. In case you were wondering how H2O is made – the H atoms from acetic acid combine with oxygen. 2H atoms + O = H2O. This explains why the expanded general formula for aerobic metabolism is HydroCarbon Fuels* + O2 –> CO2 + H2O + Heat.

* Carbohydrates are just a mix of carbon, hydrogen, and oxygen. But only the carbon combines with O2 to make CO2.

#3 – CO2 is not Necessarily the Only Gas People Exhale

Dogs can smell other gases coming out of your mouth, for example gases produced by cancer cells or gases that originate from your intestines from a crappy diet, which then absorb into your bloodstream. More on this later.

Next, Part 8: Fat (not glucose) is the Main Fuel for the Body.